# Copyright (c) 2013 Red Hat, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. from time import time from traceback import format_exc from eventlet import Timeout from swift.common.swob import Request from swift.common.swob import HTTPBadRequest, HTTPForbidden, HTTPNotFound, \ HTTPSeeOther from swift.common.middleware.acl import clean_acl, parse_acl, referrer_allowed from swift.common.utils import cache_from_env, get_logger, \ split_path, config_true_value class KerbAuth(object): """ Test authentication and authorization system. Add to your pipeline in proxy-server.conf, such as:: [pipeline:main] pipeline = catch_errors cache kerbauth proxy-server Set account auto creation to true in proxy-server.conf:: [app:proxy-server] account_autocreate = true And add a kerbauth filter section, such as:: [filter:kerbauth] use = egg:swift#kerbauth See the proxy-server.conf-sample for more information. :param app: The next WSGI app in the pipeline :param conf: The dict of configuration values """ def __init__(self, app, conf): self.app = app self.conf = conf self.logger = get_logger(conf, log_route='kerbauth') self.log_headers = config_true_value(conf.get('log_headers', 'f')) self.reseller_prefix = conf.get('reseller_prefix', 'AUTH').strip() if self.reseller_prefix and self.reseller_prefix[-1] != '_': self.reseller_prefix += '_' self.logger.set_statsd_prefix('kerbauth.%s' % ( self.reseller_prefix if self.reseller_prefix else 'NONE',)) self.auth_prefix = conf.get('auth_prefix', '/auth/') if not self.auth_prefix or not self.auth_prefix.strip('/'): self.logger.warning('Rewriting invalid auth prefix "%s" to ' '"/auth/" (Non-empty auth prefix path ' 'is required)' % self.auth_prefix) self.auth_prefix = '/auth/' if self.auth_prefix[0] != '/': self.auth_prefix = '/' + self.auth_prefix if self.auth_prefix[-1] != '/': self.auth_prefix += '/' self.token_life = int(conf.get('token_life', 86400)) self.allow_overrides = config_true_value( conf.get('allow_overrides', 't')) self.storage_url_scheme = conf.get('storage_url_scheme', 'default') self.ext_authentication_url = conf.get('ext_authentication_url') if not self.ext_authentication_url: raise RuntimeError("Missing filter parameter ext_authentication_" "url in /etc/swift/proxy-server.conf") def __call__(self, env, start_response): """ Accepts a standard WSGI application call, authenticating the request and installing callback hooks for authorization and ACL header validation. For an authenticated request, REMOTE_USER will be set to a comma separated list of the user's groups. If the request matches the self.auth_prefix, the request will be routed through the internal auth request handler (self.handle). This is to handle granting tokens, etc. """ if self.allow_overrides and env.get('swift.authorize_override', False): return self.app(env, start_response) if env.get('PATH_INFO', '').startswith(self.auth_prefix): return self.handle(env, start_response) token = env.get('HTTP_X_AUTH_TOKEN', env.get('HTTP_X_STORAGE_TOKEN')) if token and token.startswith(self.reseller_prefix): groups = self.get_groups(env, token) if groups: user = groups and groups.split(',', 1)[0] or '' trans_id = env.get('swift.trans_id') self.logger.debug('User: %s uses token %s (trans_id %s)' % (user, token, trans_id)) env['REMOTE_USER'] = groups env['swift.authorize'] = self.authorize env['swift.clean_acl'] = clean_acl if '.reseller_admin' in groups: env['reseller_request'] = True else: # Invalid token (may be expired) return HTTPSeeOther( location=self.ext_authentication_url)(env, start_response) else: # With a non-empty reseller_prefix, I would like to be called # back for anonymous access to accounts I know I'm the # definitive auth for. try: version, rest = split_path(env.get('PATH_INFO', ''), 1, 2, True) except ValueError: version, rest = None, None self.logger.increment('errors') # Not my token, not my account, I can't authorize this request, # deny all is a good idea if not already set... if 'swift.authorize' not in env: env['swift.authorize'] = self.denied_response return self.app(env, start_response) def get_groups(self, env, token): """ Get groups for the given token. :param env: The current WSGI environment dictionary. :param token: Token to validate and return a group string for. :returns: None if the token is invalid or a string containing a comma separated list of groups the authenticated user is a member of. The first group in the list is also considered a unique identifier for that user. """ groups = None memcache_client = cache_from_env(env) if not memcache_client: raise Exception('Memcache required') memcache_token_key = '%s/token/%s' % (self.reseller_prefix, token) cached_auth_data = memcache_client.get(memcache_token_key) if cached_auth_data: expires, groups = cached_auth_data if expires < time(): groups = None return groups def authorize(self, req): """ Returns None if the request is authorized to continue or a standard WSGI response callable if not. Assumes that user groups are all lower case, which is true when Red Hat Enterprise Linux Identity Management is used. """ try: version, account, container, obj = req.split_path(1, 4, True) except ValueError: self.logger.increment('errors') return HTTPNotFound(request=req) if not account or not account.startswith(self.reseller_prefix): self.logger.debug("Account name: %s doesn't start with " "reseller_prefix: %s." % (account, self.reseller_prefix)) return self.denied_response(req) user_groups = (req.remote_user or '').split(',') account_user = user_groups[1] if len(user_groups) > 1 else None # If the user is in the reseller_admin group for our prefix, he gets # full access to all accounts we manage. For the default reseller # prefix, the group name is auth_reseller_admin. admin_group = ("%sreseller_admin" % self.reseller_prefix).lower() if admin_group in user_groups and \ account != self.reseller_prefix and \ account[len(self.reseller_prefix)] != '.': req.environ['swift_owner'] = True return None # The "account" is part of the request URL, and already contains the # reseller prefix, like in "/v1/AUTH_vol1/pictures/pic1.png". if account.lower() in user_groups and \ (req.method not in ('DELETE', 'PUT') or container): # If the user is admin for the account and is not trying to do an # account DELETE or PUT... req.environ['swift_owner'] = True self.logger.debug("User %s has admin authorizing." % account_user) return None if (req.environ.get('swift_sync_key') and (req.environ['swift_sync_key'] == req.headers.get('x-container-sync-key', None)) and 'x-timestamp' in req.headers): self.logger.debug("Allow request with container sync-key: %s." % req.environ['swift_sync_key']) return None if req.method == 'OPTIONS': #allow OPTIONS requests to proceed as normal self.logger.debug("Allow OPTIONS request.") return None referrers, groups = parse_acl(getattr(req, 'acl', None)) if referrer_allowed(req.referer, referrers): if obj or '.rlistings' in groups: self.logger.debug("Allow authorizing %s via referer ACL." % req.referer) return None for user_group in user_groups: if user_group in groups: self.logger.debug("User %s allowed in ACL: %s authorizing." % (account_user, user_group)) return None return self.denied_response(req) def denied_response(self, req): """ Returns a standard WSGI response callable with the status of 403 or 401 depending on whether the REMOTE_USER is set or not. """ if req.remote_user: self.logger.increment('forbidden') return HTTPForbidden(request=req) else: return HTTPSeeOther(location=self.ext_authentication_url) def handle(self, env, start_response): """ WSGI entry point for auth requests (ones that match the self.auth_prefix). Wraps env in swob.Request object and passes it down. :param env: WSGI environment dictionary :param start_response: WSGI callable """ try: req = Request(env) if self.auth_prefix: req.path_info_pop() req.bytes_transferred = '-' req.client_disconnect = False if 'x-storage-token' in req.headers and \ 'x-auth-token' not in req.headers: req.headers['x-auth-token'] = req.headers['x-storage-token'] return self.handle_request(req)(env, start_response) except (Exception, Timeout): print "EXCEPTION IN handle: %s: %s" % (format_exc(), env) self.logger.increment('errors') start_response('500 Server Error', [('Content-Type', 'text/plain')]) return ['Internal server error.\n'] def handle_request(self, req): """ Entry point for auth requests (ones that match the self.auth_prefix). Should return a WSGI-style callable (such as webob.Response). :param req: swob.Request object """ req.start_time = time() handler = None try: version, account, user, _junk = req.split_path(1, 4, True) except ValueError: self.logger.increment('errors') return HTTPNotFound(request=req) if version in ('v1', 'v1.0', 'auth'): if req.method == 'GET': handler = self.handle_get_token if not handler: self.logger.increment('errors') req.response = HTTPBadRequest(request=req) else: req.response = handler(req) return req.response def handle_get_token(self, req): """ Handles the various `request for token and service end point(s)` calls. There are various formats to support the various auth servers in the past. Examples:: GET /v1//auth GET /auth GET /v1.0 All formats require GSS (Kerberos) authentication. On successful authentication, the response will have X-Auth-Token set to the token to use with Swift. :param req: The swob.Request to process. :returns: swob.Response, 2xx on success with data set as explained above. """ # Validate the request info try: pathsegs = split_path(req.path_info, 1, 3, True) except ValueError: self.logger.increment('errors') return HTTPNotFound(request=req) if not ((pathsegs[0] == 'v1' and pathsegs[2] == 'auth') or pathsegs[0] in ('auth', 'v1.0')): return HTTPBadRequest(request=req) return HTTPSeeOther(location=self.ext_authentication_url) def filter_factory(global_conf, **local_conf): """Returns a WSGI filter app for use with paste.deploy.""" conf = global_conf.copy() conf.update(local_conf) def auth_filter(app): return KerbAuth(app, conf) return auth_filter